The present invention relates generally to planar antennas and, more particularly, to planar inverted “F” antennas that can be flexed without degrading antenna performance.
The need for planar antennas has grown tremendously due to the proliferation of all kinds of hand-held and portable wireless devices where the area reserved for antenna location continues to shrink. This need has been met by planar antennas, especially those known as planar inverted “F” antennas, or PIFAs. As shown in FIG. 1, a PIFA 10 basically comprises a main conductive element 12 that is positioned in a parallel position above a ground plate 14 via a short circuit plate or pin 16 that is located on aligned sides of the main element 12 and the ground plate 14. An antenna feed point 18 is formed on the main element 12. A PIFA is basically a monopole antenna that has been folded down to be parallel with the ground plate. An air gap resides between the main element 12 and the ground plate 14. PIFAs often perform better than other types of antenna. PIFAs are typically attached to flat surfaces 17 as shown in FIG. 1.
However, there remains a need to provide for a flexible PIFA that can be used on various kinds of articles (e.g., curved enclosures, wearables, etc.) that do not include flat surfaces for mounting without degrading the PIFA antenna performance. In addition, this need also includes providing a PIFA that is less sensitive to the presence of a living body in the near field, as well as being less sensitive to the presence of metal, than are traditional antennas.
All references cited herein are incorporated herein by reference in their entireties.